Research regarding the use of South Africa’s platinum-group metals (PGMs) in fuel cells and water electrolysis will enable electrification of remote communities and the use of hydrogen as a primary energy carrier in future.

Hydrocarbons, mostly petroleum distillates and natural gases, are primary sources of energy, but the generation of hydrogen and oxygen through water electrolysis can allow for the storage of energy from variable and renewable sources, says Department of Science and Technology research organisation Hydrogen South Africa (HySA) infrastructure centre director Dr Dmitri Bessarabov.

Developments for hydrogen fuel cells, which react hydrogen and oxygen in the presence of a catalyst to produce electricity and water, have progressed significantly and can enable the electrification of remote communities without the cost of constructing transmission lines.

PGMs, of which South Africa has significant reserves, are being developed to produce more efficient catalysts to accelerate the reaction rate in electrolytic and fuel-cell reactions.

The catalysts used in the two reactions are similar, as the reactions are basically mirror reactions, with the one drawing energy to split the molecule of water to produce oxygen and hydrogen and the other combining these elements to produce electricity and water.

Hydrogen gas can be generated and stored by splitting water in polymer electrolyte membrane (PEM) electrolysers, and the hydrogen can act as an energy storage medium, also known as an energy carrier.

“These systems can offer a fast response to volatile renewable-energy sources. Owing to the use of a dense proton-exchange membrane, PEM water electrolysis systems are capable of producing hydrogen at relatively high and practical discharge pressures, suitable, for example, for injecting hydrogen into the grid of natural gas pipes,” he explains.

The efficiency of the renewable-energy source would have to meet only a minimum threshold and can result in current renewable technologies being deployed, emphasises Bessarabov.

“Because the system stores energy by splitting the hydrogen and oxygen of water, the efficiency of the renewable source is not as critical as it would be for its immediate use, as long as it is above the minimum requirement of the application in question.”

However, the requirements for hydrogen infrastructure also need to be better understood, he says.

The high cost of associated infrastructure must be acknowledged and balanced against improving the quality of life for people not yet connected to the electricity grid, he adds.

“Part of HySA’s objective is to bring small, medium-sized and microenterprises into this hydrogen fuel cell value chain. This would require them to understand the benefits of hydrogen as a renewable-energy source.”

Over the past two years, the HySA infrastructure centre has produced a number of significant technology demonstrators in the hydrogen and fuel cell technology sector.

“We have completed a Generation 2 hydrogen PEM water electrolysis plant that produces up to 3 kg of hydrogen a day using solar energy. This is equivalent to about 12 ℓ of petrol.

Since its establishment in 2007, HySA’s mandate from Cabinet has been to promote the development of high-technology manufacturing of hydrogen fuel cell and electrolysis components.

However, significant work has still to be done to develop the local capacity, skills and relevant supply chains, notes Bessarabov.

Companies in industry should approach HySA to determine potential applications of hydrogen technologies or the possibility producing components for hydrogen technology equipment.